Learn Italian: Il documento ha dieci parole. - The document has ten words.

No. While the number one changes to match gender (un documento, una parola), all other numbers from 2 to 10 stay exactly the same. You will use dieci whether the following noun is masculine or feminine.

Why does the word for "words" end in "-e" (parole)?

The singular word for "word" is parola. It is a feminine noun ending in -a. In Italian, most feminine nouns that end in -a change their ending to -e when they become plural.

How do you pronounce ha, and why is the "h" there?

The letter "h" is always silent in Italian, so ha is pronounced exactly like the English letter "ah". The "h" is only written here to tell the difference on paper between the verb ha (has) and the little word a (to/at).

Is documento masculine or feminine?

It is masculine! You can usually tell because it ends in -o in the singular. Because it is a masculine word starting with a standard consonant (d), it takes the singular definite article il (the).