If you are unable to find a particular Pair/Instrument on MetaTrader, you will need to select "Show all" in the Market Watch section.
Right-click on the Pair/Instrument section
Choose "Show All"
If you are on a mobile/tablet:
To be able to add more Pairs/Instrument on a mobile device, you will need to click on the “+” icon on the top right-hand side of your screen as shown below.
You will need to choose the appropriate category.
Then you will need to choose the pair/instrument you want to see.