Start with what you can see
Open WhatsApp on your primary phone and find Linked devices in its settings or menu. Review the sessions listed. A familiar browser or computer can explain a session you had forgotten about; a name alone is not proof of who used it.
Remove access you do not recognise
Select an unfamiliar linked device and use the logout option. Use the official WhatsApp app and current Help Center instructions if the menu differs on your phone. Review sessions periodically, especially after using a shared computer.
Keep the next step simple
Do not send anyone your registration codes, passwords or recovery information. If access problems continue, follow WhatsApp’s official help. A linked-device review is one useful account check, not a complete investigation of your phone. Chochote can help you discuss an authorised review and its limits.
Official sources & further reading
Interfaces and advice can change. Check the provider’s current instructions for your device.