By the LinkDrop team.
Facts about Gmail and Outlook come from Google's and Microsoft's own help pages, linked below and read on October 19, 2026. Facts about LinkDrop come from its help center and the product itself.
The short answer
Attach the PDF when the reader needs to keep the file, work offline, or file it somewhere, and you do not need to know what happens next.
Send a tracked link when you want to know whether it was read, may need to change it after sending, or may want to take it back.
Most people sending a deck, a proposal or a report to someone outside their company want the second.
What an attachment is
An attachment is a copy. The moment you press send, the recipient has the file and you do not control it any more. That is simple and dependable, and it is also the whole problem:
- You cannot see it. Nothing in a PDF reports that it was opened.
- You cannot change it. A corrected version is a second email, and both copies stay in their inbox.
- You cannot take it back. It can be forwarded, saved and re-sent without you knowing.
"But email has read receipts"
Read receipts tell you about the email, not the file, and they are unreliable on purpose:
- Microsoft: "the message recipient can decline to send read receipts", and "there is no way to force a recipient to send a read receipt" (Microsoft Support, read 2026-10-19).
- Google: read receipts "are only available to work or school accounts" and "don't work with personal Gmail (@gmail.com) accounts"; the recipient "may need to approve it first" (Gmail Help, read 2026-10-19).
Even a returned receipt says only that the message was opened. Not the PDF, not which pages, not for how long.
Size limits
Gmail limits attachments on personal accounts to 25 MB. Over that, Google says, "Gmail automatically removes the attachment and adds it as a Google Drive link in the email" (Gmail Help, read 2026-10-19). On work and school accounts the administrator sets the limit.
What a tracked link is
A tracked link sends the reader to a page that shows the PDF. The file stays with you. The page records the visit.
In LinkDrop, that means:
- You see who read it: each page they viewed, the time on each page, and whether they came back. You can get an email when someone first opens the link, and, using credits, a short written brief after a visit worth one. See Analytics.
- You can change it: Upload new version puts the new file behind the same link. Every link keeps its address and its analytics, and readers see the new version straight away. On Pro, if a teammate should check it first, save it as a draft; readers never see drafts. See Versions and history.
- You can take it back: disable the link and it stops working at once. The reader sees "This link isn't available", and nothing about the document shows, not even its title in a link preview.
- You choose what they can do: downloads are off on a new link unless you allow them, and you can add a password or an expiry date. See Share links.
The reader needs no account and no app. The link opens in a browser. If you received a link explains to a reader what they will see and what you will see.
Side by side
| Email attachment | LinkDrop link | |
|---|---|---|
| Know it was opened | Only via a read receipt, which the reader can decline, and which covers the email, not the PDF | Yes, with an optional email within about five minutes |
| Pages read and time per page | No | Yes |
| Fix it after sending | Send another email | Upload a new version; same link |
| Take it back | Only within seconds of sending (Gmail Undo Send) or inside one organization (Outlook recall) | Disable the link |
| Reader can keep a copy | Always | Only if you allow downloads, or approve their request |
| Works offline | Yes | No, needs a connection |
| Size | 25 MB on personal Gmail; set by the admin on work accounts | PDFs up to 50 MB and 300 pages |
| Reader needs | An email client and a PDF reader | A web browser |
| File types | Most types (Gmail blocks some, such as .exe) | PDF only |
| Reader privacy | The sender learns nothing beyond a read receipt the reader chose to send | The sender sees their reading; they stay anonymous unless they sign in, introduce themselves or ask to download |
Where attachments are better
Be honest about this. An attachment is the right choice when:
- The reader must keep the file, such as a signed contract, an invoice, or anything for their records.
- The reader will be offline, on a plane or anywhere without a connection.
- It is not a PDF, such as a spreadsheet they need to edit.
- You do not need to know. A tracked link is a small extra step for no gain if nobody will look at the numbers.
- The recipient expects not to be tracked. Some people and some organizations prefer a plain file, and that is a fair preference.
Where a tracked link is better
- You will follow up, and want to know when and how.
- The document will change: a proposal, a deck, a price list.
- It is confidential, and you may want to stop access later.
- You are sending one document to many people and want to know who engaged.
How to switch
- Upload the PDF to LinkDrop.
- Make a link per recipient, labelled with their name. The label is private; the reader never sees it.
- Paste the link into the email where the attachment would have gone.
How to track when someone opens a PDF walks through these steps with screenshots and a video.
Each recipient's link has its own settings and its own numbers, so you can see who read it and turn one off without touching the others. Free covers 10 shared documents, with the same reader analytics as Pro; see Pricing.