Open Settings from the user menu in the sidebar. It opens over the page rather than navigating away. Your details are under Account, and how the app looks is under General.
Your details
Name and email under Account. Your name appears on shared chats and docs, so it is worth having it right before you share anything.
Password
Change it under Account. If you signed in with Google there is no password here to change, because your Google account handles it, and the page says so rather than showing you a dead field.
Theme
Settings, then General, then Appearance. Light, dark, or follow your system.
Interface language
Six languages: English, German, Spanish, French, Hungarian and Russian.
Change it from the Language menu in the sidebar. There is no language page, and this is the part people look for in the wrong place.
This changes the interface only. It does not change what Vamos writes for you, which follows your prompt and your brand. If you want output in another language, ask for it in the chat or put it in My Brand.
Deleting your account
Under Account, and it is permanent. Every workspace, chat, doc, Watchlist and brand goes with it.
If what you want is to stop paying, cancel the subscription instead and keep the account on the free plan. See Managing your subscription.