Best way to translate or modify theme or plugin strings
Hard coded gettext strings translation
All hard coded texts within themes or plugins can be translated by using a po file editor such as:
Loco Translate Plugin (Free)
PoEdit PRO (Paid)
WPML Plugin (Commercial)
Dynamic String Translation
If you need to translate dynamic strings, usually set within plugin settings or customizer options, PoEdit and LocoTranslate will NOT work since they can only translate hard coded gettext strings.
In that case, you can use TranslatePress, a free plugin to visually and easily translate any string on your site, directly on your frontend:
Screenshots