What to include so a reply is useful
Name the tool exactly as it appears in the title, for example PDF to Word or MP4 to MKV. Say what you uploaded, what you expected to download, and what you got instead. A sentence such as "it did not work" is not enough, because many tools are working as designed and the limit is written on the page. If the page says a scan has no text, or that a browser cannot write HEIC, email will not change that.
Do not attach the file if it contains anyone else's personal data, a password, or a private document. Describe the page count, the format, and the error text instead. Most conversions never reach us. They run in your browser. The contact form sends only the name, email, subject, and message you type. YouTube tools are different: they send the video link so a public stream can be fetched, and they do not store the file as a library.
What a message can and cannot fix
A message can tell us that a download does not match the description on the tool page, or that a button fails on a normal file the page claims to support. It can also carry a copyright notice. It cannot change a government portal's kilobyte cap, a university's CGPA formula, or YouTube's decision to block a fetch. Those rules live outside this site.
Copyright notices belong on the DMCA page as well as here. Include the URL on this site, the work you own, and a way to reply. A notice without the URL cannot be matched to a page.
We read messages in the order they arrive and aim to reply within a few business days. The response time on the card is the goal, not a promise that a broken conversion will be rebuilt into a different product. If the tool page already states the limit, the useful next step is a different tool or a desktop app, not a wait for email.
Partnership notes can use the same form. Say who you are and what you want. Do not send marketing attachments that require a login to open.