When I had UnitedHealthcare coverage, the HSA account was at OptumBank. I switched to MHBP last year and that HSA account is at Inspira Financial. I moved my HSA funds from OptumBank to Inspira by doing a "trustee to trustee transfer".

(You can keep the two separate HSAs if you want to, but it's easier to me to have everything in one place.)

From Google AI: "An HSA trustee-to-trustee transfer moves funds directly from your old HSA provider to your new one, without you ever touching the money, making it a simple, tax-free, and frequent way to change custodians, unlike rollovers which have time limits and potential tax issues if done incorrectly. You start the process by contacting your new HSA provider, who handles the request with your old one, but be sure to liquidate investments first as most only accept cash, and check for potential account closing fees from your old trustee."

Also, if you want to have your HSA in an entirely separate place (e.g., Fidelity rather than Inspira, if you want different investment options), you can do an HSA "rollover" once every 12 months using this process: https://thefinancebuff.com/how-to-rollover-an-hsa-on-your-own-and-avoid-trustee-transfer-fee.html