In order to set up Magento 2 Auto Currency Switcher Module please go to Stores > Configuration > Magefan Extensions > Auto Currency Switcher.

Magento 2 Auto Currency Switcher, General,Extension Restrictions

General

1. First of all, make sure if the extension is enabled choosing Yes in the Enable Extention select box.

2. In Round Prises select box you choose "Yes" correspondingly if you want the prices to be rounded after the conversion of the currency.

3. You can choose the algorithm prices will be rounded by in Round Algorithm.

Magento 2 Currency Switcher,General

Extension Restrictions

In User Agents you can set the user agents (bots) this module will be disabled for.
E.g.: for Google bot this module will be disabled, it will crawl the site as usual.

Magento 2 Auto Currency Switcher, General,Extension Restrictions

Display Currency By Country

In this section, you are able to choose which currency in a particular country will be shown by default.

Magento 2 Auto Currency Switcher, Display Currency By Country

Select a region and country you are interested in and set a currency from the proposed list of Allowed Currencies.

Magento 2 Auto Currency Switcher, Display Currency By Country

After finishing all of the configurations don't forget to press the Save Config button and Flush Magento Cache.

Magento 2 Save Configuration