Work from a copy and ask what the service needs to complete the task. Remove unrelated pages, embedded metadata, credentials, personal identifiers, and confidential material where possible. Check the tool's data handling and whether the file is processed locally or sent elsewhere.
Use a small synthetic sample first if you are unsure how conversion will behave. After processing, open the exported result and inspect for missing pages, altered formatting, or residual private details. Keep the original until the output is verified.
A browser tool can be convenient; convenience alone does not establish privacy.
Also inspect what the file carries besides the visible content. Photos may contain EXIF location data, PDFs can preserve author names, comments or hidden layers, and office files may include macros or revision history. Create a sanitized copy, remove unnecessary metadata and pages, and upload that copy rather than the original. Client-side processing reduces exposure, but it is still worth checking network activity and the service's retention policy.
Akousa