If you are starting a new site and/or want to use HTTPS everywhere on your site, you need to update your site URL in Settings » General by updating your WordPress and site URL address fields.
If created API’s for social logins and payment options before to add SSL you must check them and change pages url added in it.
Paypal setup: http://help.wprentals.org/article/paypal-set-up/
Stripe setup: http://help.wprentals.org/article/stripe-set-up/
Facebook login: http://help.wprentals.org/article/facebook-login/