Learn Russian: Здесь два метра.

This sentence uses a special Russian number rule. After the numbers 2, 3, and 4, nouns must take the genitive singular form rather than the normal plural. The basic dictionary word for metre is метр, and its genitive singular form is метра.

Why do we use два for the number "two"? Are there other ways to say "two"?

Yes, the number "two" changes depending on the gender of the noun you are counting. Because метр is a masculine noun, we use два. If you were counting a feminine noun, you would use две. The numbers 3 and 4 do not change for gender.

Where are the words for "It" and "is" in the Russian sentence?

In the present tense, Russian almost always skips the verb "to be" (like "is"). Furthermore, Russian doesn't use a filler subject like the English word "it" in phrases like "It is cold" or "It is two metres". The Russian sentence literally just says Здесь (Here) два метра (two metres).