How can I clear WhatsApp cache without deleting the app on iPhone?

My WhatsApp has been crashing since I updated it today. I want to clear cache but I don’t know how without deleting the app. I don’t have that phone number for that account anymore. Is there any way for me to fix it without deleting and reinstalling?. I would lose things that I don’t want to if I do it that way. Please help and thank you in advance.

regards, apple user

[Re-Titled by Moderator]