Generally polling organizations poll a random sample of Americans via phone calls or online polls. There is a lot of process to try to guarantee a representative sample.
I don't think a pollster would be disappointed that you don't have a party affiliation. In fact some of biggest emphasis in election season is on independents or undecided voters.
> In fact some of biggest emphasis in election season is on independents or undecided voters.
Exactly. You can look it up on 538 or wherever you like, but all the polls say roughly the same thing: There's more unaffiliated voters than there is voters for either party. Something like 40-45% unaffiliated, with ~25% identifying as Republican and ~30% identifying as Democrat.
I don't think a pollster would be disappointed that you don't have a party affiliation. In fact some of biggest emphasis in election season is on independents or undecided voters.