Your funds are in your wallet onchain, not on your phone. Install Legend on your new device and sign in with the same method that you used before. Your balance, positions, and history come back.

Cannot find your account? Make sure that you use the same sign-in method and the same email or social account.
Lost access to your email or social account? Get it back from that provider first, or sign in with another linked method.
Think that someone else has access? Withdraw your funds to a wallet that you control, then contact support.