How can I send a file?
Use Threema to send files of any type (PDF, animated GIF, MP3, DOC, ZIP, etc.). Just like all other messages, files are end-to-end encrypted. The maximum file size is 50 MB (it might, however, not be possible to send large files on older devices due to insufficient memory). To avoid compression of an image or video, you can send it as file. Please note: If you send an image as file, its EXIF tags (possibly containing information such as the date and location the image was taken) are preserved.
Android: In a chat, tap on the paperclip icon, and select “File”.
iOS: In a chat, tap on the “+”, and select “Send file”. Due to restrictions of iOS regarding the file system, you can only access content of apps that support file sharing.
Windows Phone: Currently not available. Files cannot be received.