If I understood your question right: You can use remote signers (nostrconnect:// / bunker://) like Amber or DENOS (or Primal now?), local PC signers and with username/pass like DENOS, browser extension, or import your 24 words or nsec for local use, or generate a new one. Basically all popular options are there + the stuff I made (pc local, username/pass, dnn)