Can I buy a SIM card in the USA and keep it to use every time I visit the USA?

The duration between visits and amount of expected use will matter a lot in this case, you should mention it.

This information is a bit outdated as I haven't done recent research, but TMobile prepaid (and I think also AT&T) had 1 year expiration for SIMs charged with initial payment of $100. If you topped up again within a year, the clock would reset (so for e.g. if you visit every 11 months, you'd top up your account with $10 and keep the number).

But this only applies if you want to keep the same number, otherwise you probably don't want so much expenditure just for a few calls to Uber. It would be simpler to just buy a new prepaid activation kit for each visit, and have a Google voice number for any contacts who may call up.

If you visit more often, within 120 days, and won't be using the line much other than just hailing rideshares, maybe other MVNOs are a better fit. Searching for 'emergency use sim' gives good data on medium-term duration cheap plans, and useful discussion in threads like this one.

The bigger providers of pre-paid plans allow you to switch back & forth between a monthly data/talk plan (when you are in the states) and a pay as you go plan (when you are outside). This is how I maintain my US mobile number while I am home in SE Asia.

The pay as you go charge you 10 cents per minute for calls and texts and no data, with a minimum charge of $3 per month. But this $3 monthly fee keeps your number / SIM active when you are away from the states.

You can top up your account online in large increments, such as $100 with a one year validity, or in smaller amounts on a more frequent basis.

If you simply pay the $100 top up, but then disable your data plan, your sim and number will expire within six months, even though your payment credit last longer. You need to maintain some sort of calling or data plan on your number for the SIM & number to stay active.

So you really need to ask, is the keeping the SIM & number worth cost (say 9 months @$3). Buying a new SIM is pretty cheap with pre-paid service providers.

Get a Project Fi SIM

Use it as much as you want then pause the service once you are out. I did that for over a year, although I resumed the service when I was traveling in Europe for time to time.

Port your phone to Google Voice once you leave US

Never tried that, but you can get a prepaid SIM card, then you port over the number to Google Voice. The advantage here is that you will still be able to receive the calls and texts from your Gmail account. Be careful that in the US some carriers may block you from porting your number away. I had Simple Mobile and they tried to block my porting for hours, falsely claiming that the address provided did not match the one they had. I heard that many other people had this problem. Check for a carrier that will not make that task difficult.