There are following below steps need to follow, Magento 2 Admin
[1]- Go To STORES > Configuration, redirects on configuration.
[2]- Left Panel Clicked on General > Currency Setup, redirects on [Right Panel]
[3]- Once redirection on [Right Panel]
[4]- Once clicked / expanded, Currency Options [Right Panel]
Each Input field (Select Box Values), defined as
[4.1]- Base Currency : Select Base Currency (Main Currency) for online payment transaction, By Default US Dollar Selected
[4.2]- Default Display Currency :Select Default Display Currency that Store Owner(Admin) want to display pricing in store.
By Default US Dollar Selected.
[4.3]- Allowed Currencies : Select list of currencies that Store Owner(Admin) want to allow, in case of Multiple Currency( By Using to hold the ctrl key and then selecting the currency options).
During above operation, if message as cache refreshment display, then close it and refresh it.
[5] Set scope of the base currency:
[5.1]- Once clicked on Left Panel (Catalog > Catalog)
[5.2]- Display Right Panel (Price)
Select Catalog Price Scope as either “Global” or “Website”
[6]- Finally click on Save Config Button