I have 2018 Adobe Illustrator and 2018 Adobe Photoshop, How to update them to current Versions?

If you have Creative Cloud (CC) versions of Illustrator & Photoshop then you update & upgrade via the Adobe Creative Cloud app. Be aware, however, that you must have a current subscription in order to update/upgrade this way.

If for some reason you do not have the Creative Cloud app on your Mac, you will have to log into your Adobe account via the web, download & install it. Then you can check if your subscription is active and if so then update/upgrade your Adobe apps.

Oftentimes apps will have an update link for you to click on. It might be located in Preferences or under Help. I think you are going to have to visit Adobe's web site to get your updates and there will likely be a cost involved.