The name in Spanish is: "Infinitivo"
Infinitive is the most important form of a verb and it is one of the three impersonal forms in Spanish (together with gerund and participle).
Infinitive can ends in "-ar", "-er" or "-ir".
Examples:
hablar
to speak
comer
to eat
dormir
to sleep
The infinite is used:
Ahorrar es muy importante
Saving is very important
Me gusta comer mucho
I like to eat a lot
Quiero un móvil fácil de usar
I want a easy to use phone