How?

No it cannot, sorry.
Are you trying to do that for address?

How to set the width of the contact form fields
https://www.fastsecurecontactform.com/tip-setting-width

i copy sorce html code of form from browser and edit some div’s
and paste at the post without formating and it works
but dont works redirect and thanks message
but I’ll think of something that

tip-setting-width dont for option select box for me (((
for other fields it work

You can also add width:300px; to the the following setting:
“CSS style for contact drop down select on the contact form:”
(change 300 to whatever width in pixels you want)