How to change http to https URL in WordPress and Site Addresses?

Good afternoon @Riku_Kobayashi or anyone else. Still seeking some assistance and an answer please. This is quite urgent, as it it effecting our wildlife conservation nonprofit's work. Thank you

Hello.

This question is about WordPress, not Lightsail, so I think it would be a good idea to ask your question on the WordPress support forum from the URL below.
https://wordpress.com/forums/forum/support/

You can change the site URL by following the steps in the document below.
https://developer.wordpress.org/advanced-administration/upgrade/migrating/

Hello @Riku_Kobayashi Thank you for your reply and your suggestion. However, WordPress Support directed me to AWS Lightsail, as our host, because, according to WordPress Support, the solution is for the host not WP. As to your suggested link; again thank you but baring in mind we are new to WP and new to AWS Lightsail, are you telling us that every WP site hosted with Lightsail must go through this complex coding and editing process simply to use https://. Forgive my observation but that seems ridiculously complicated. When we put this suggestion to WP they informed us this would still not work as our WP is in Lighsail. Further guidance would be appreciated please.