TypeSquare web fonts are applied only to the sentences which are originally written in the text of web pages.
It cannot be applied to sentences added using scripts, etc. after pages have been loaded.

Please note that TypeSquare web fonts are basically set not to be applied to a text field form even if they are distributed characters in order to prevent the characters from being mixed with already distributed ones and undistributed ones.

[Solution]
If you select a Standard Pro plan, you can use TypeSquare API which enables you to apply the web fonts to the characters added in the form once the page including the characters is reloaded.
See the following information according to the version of TypeSquare API you are using:
*Please note that it may result in excess of the number of distributable PV because a PV will be consumed per loading the font.
*Please see this FAQ to confirm the version of the plan tag that you are using.

■ For customers who are using our newer version of the plan tag (typesquare.js v3)
You can use a font autoloading function.
For more details, please see TypeSquare API v3 Reference.
https://typesquare.com/en/service/api_reference

■ For customers who are using our previous version of the plan tag (typesquare.js v2)
You can use a dynamic CSS request and a dynamic JSON request.
For more details, please see TypeSquare API v2 Reference.
https://typesquare.com/en/service/api_reference_v2