You may be using samsungs email app but it will be tied to Gmail, you'd need to follow the steps to reset your password at Google.co.uk and clicking on the word gmail top right hand side of the webpage.
Or a n other mail service. Not everyone uses Gmail. AOL, Yahoo!, Microsoft Hotmail/Outlook, Proton, O2, Vodafone, Talk talk etc. The OP should try using the webmail site in their browser to reset the forgotten password.