Field Limits

FieldLimit
username1-80 characters
content2000 characters
embeds10 embed objects
title*256 characters
description*4096 characters
author.name*256 characters
fields25 field objects
field.name*256 characters
field.value*1024 characters
footer.text*2048 characters
file (not actual field name)10 files
sum of characters in marked fields6000 characters

Discord API reference