This property defines the maximum number of characters that your users will be allowed to enter in a field. The maximum value that you can set for this property is 255. Refer to this page to learn how to set max characters.

Maximum character length validation will be implemented strictly for all your form fields if a record is added via Deluge, API, or email input. This validation ensures that all the records added via various inputs undergo a thorough check for their field characters to ensure they're on par with the predefined character limits that you set, thereby minimizing error handling.
For example, when you set the Max Characters property for a single line field on your form to 50, the below given will be the user experience on your form,
- Understand fields
- Set maximum characters