Hi,
MapPress supports standard WordPress translation techniques, but they’re not always easy:
This used to work, but I’m not sure it’s still supported: https://mappresspro.com/translating-mappress/
More recently, WordPress now wants translators to provide a complete translation. Here’s a tutorial:
https://www.wpbeginner.com/wp-tutorials/how-to-translate-a-wordpress-plugin-in-your-language/
Finally, there are various translation plugins which may work for you, and they can make this easier (especially for just one string).