Each state has some form of restriction on political activities near polling places when voting is taking place, such as limiting the display of signs, handing out campaign literature or soliciting votes within a pre-determined distance (typically 50 to 200 feet) of a polling place. Some states also address what apparel voters can wear within polling places.
In summary:
21 states prohibit campaign apparel/buttons/stickers/placards.
38 states and Washington, D.C., prohibit campaign materials/signs/banners/literature.
29 states prohibit influencing voters/soliciting votes/political persuasion.
18 states and Washington, D.C., prohibit circulating petitions/soliciting signatures.
10 states prohibit projecting sounds referring to candidates/issues.
6 states prohibit polls/exit polls.
9 states prohibit loitering.
3 states prohibit peddling/advertising.
10 states prohibit voter intimidation/interfering with voter.
10 states prohibit obstructing entrance/hindering voter.
https://www.ncsl.org/elections-and-campaigns/electioneering-prohibitions
There is a breakdown of electioneering prohibitions and apparel guidelines by state in that article as well
