I’m sorry but can you please share more details on what you’re looking for / your use-case? Do you wish to update the email address when a person fills out the form (that doesn’t make much sense though) or based on the post title do you want update the submit button text/modify default submit button actions?
Yep, I'm with Darshil_Shah1, we need a little more info. The form itself, by default, doesn't submit to an email address, but if it is setup to do so via smart campaign upon form fill, you'll have to change it in the campaign, not on the form itself.
If you're unsure of where that might be, you can go to the form asset, select it and view the "Used By:" information that appears to it's right to view the campaigns that use this form as a trigger and what not.