Yes, you can.
When publishing or requesting approval
There are character limits for titles and descriptions.
Please adjust the title and description to be within the character count displayed on the editing screen.
When saving as a draft
There are the following differences between the web browser version and the mobile app.
Web Browser Version
You can save a draft of a manual that contains a cover or steps exceeding the character limit for titles and descriptions.
Mobile App
When content saved as a draft in the web browser version exceeds the publishable character count
As long as it's within the character count entered in the web browser version, you can save a draft that exceeds the publishable character limit.
When content saved as a draft in the web browser version is within the publishable character count
As usual, you can save a cover or step as a draft if it's within the publishable character limit.
Related: Please tell me the maximum values for various elements that can be registered in Teachme Biz
https://help.teachme.jp/hc/en-us/articles/6436034396441