Hello Waheedha Jareen Choudhury,

You need to configure to remove the option to log in on the website

Open the website editor mode and click on the edit button top right corner.

Then select the header part of the website and you will see the "Show Sign in" option. please turn off the "Show Sign in" button and click on the Save button. 

I hope this solution is helpful for you.

Thanks & Regards,
Email: odoo@aktivsoftware.com
Skype: kalpeshmaheshwari