How can I see all the pairs that are on MetaTrader?

You will need to right-click on any pair/instrument and click on Show All.

Mobile app:

If you are using the Mobile application, you will need to click on symbol that is on the top right-hand side of the screen.

Choose the appropriate category.

Choose the pair/instrument you want to see.

The instrument/pair will now be available in the Quotes section.