The maximum file size when submitting assignments or attaching files to forum discussions is usually 100MB.
Max File size for assignment uploads is displayed when you attach files:
Max File size for forum post attachments is displayed when you attach files:
Note: If your file is a video or audio file, you can upload it using My Media. My Media helps you upload video and audio files to Moodle with almost no file size or file type restriction. To learn more about how to upload your video or audio file using My Media, review the article Moodle My Media - How to upload and share video & audio.