You can use the Trim trailing whitespace feature to ensure that any extra spaces at the end of a text field's value are not saved to Airtable. This feature is turned on by default for new single line and long text fields, but if you want to turn this on for your existing field, go to:
Your form's fields list
Select the field you want to trim automatically
Go to the Advanced section
Turn on Trim trailing whitespace
When a form saves a single line or long text value, miniExtensions also removes invisible zero-width space and byte-order-mark characters. These characters can be introduced when users copy and paste text from other sources. Any visible Unicode characters are preserved.