Learn Italian: Mangio molta verdura. - I eat a lot of vegetables.

In Italian, verdura is usually used as a collective noun. It works like the English word "produce" or "fruit". Even though you are eating multiple vegetables, the word itself is singular and feminine.

Why does the sentence use molta instead of molto?

Here, the word for "a lot of" is describing the noun verdura, which is feminine singular. Because it acts as an adjective, it changes its ending to match the noun, becoming molta.

Where is the word for "I" in the Italian sentence?

The word for "I" is io, but Italians usually drop it. The verb mangiare (to eat) changes to mangio for the "I" form. The -o at the end already tells the listener exactly who is eating.

Does the word molto always change its ending like this?

No. When it means "very" and describes an adjective (like "very good"), it stays as molto. But when it means "a lot of" and describes a noun, like in this sentence, it has to match the gender and number of that noun.