Yes, you can.
When publishing or submitting for approval
There are character limits for titles and descriptions.
Please adjust the title and description so that they are within the character limits 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 manual as a draft even if it contains a cover page or steps where the title or description exceeds the character limit.
Mobile app
When the content saved as a draft in the web browser version exceeds the publishable character limit
As long as it is within the number of characters entered in the web browser version, you can save a draft even if it exceeds the publishable character limit.
When the content saved as a draft in the web browser version is within the publishable character limit
As usual, you can save the cover page or step as a draft as long as it is within the publishable character limit.
Related: What are the maximum values for the various elements that can be registered in Teachme Biz?
https://help.teachme.jp/hc/en-us/articles/6436034396441