[Need advice] Keeping US Sim/number active while in India

Hey folks, I have to go back to India for about a year or two and I want to keep my number active till I come back. Those who have done this previously, what are the do's and don'ts that you figured out. What plan did you change to. Did you face any international charges? I'm currently in an AT&T postpaid family group and trying to get out and switch to prepaid. Any suggestions for cheapest plans or ports to maintain the US number to receive messages and Auth/OTP codes. Are there any alternatives? Not much of a data user. Want to keep this number because it is tied to multiple things and accounts. #travel #india #US #AT&T #mobile #phone TC : 330k YOE : 4.5