Questions & Answers about Я кладу фрукты в корзину.
The infinitive is класть (to put, to lay).
Russian often has stem changes between the infinitive and the 1st person singular:
- infinitive: класть
- 1st person sg. present: я кладу
- 2nd person sg.: ты кладёшь
- 3rd person sg.: он/она/оно кладёт
- 1st person pl.: мы кладём
- 2nd person pl.: вы кладёте
- 3rd person pl.: они кладут
So кладу is just the irregular present-tense form of класть. You need to memorize this pattern; it’s very common and considered basic vocabulary.