Learn Russian: Здесь текст четыре.

In Russian, just like in English, we often use standard counting numbers to label items in a sequence. Saying текст четыре (text four) is a common and natural way to identify it, just like "room two" or "bus five".

Where is the word for "is" in this sentence?

Russian typically drops the verb "to be" (am, is, are) in the present tense. You do not need a word for "is" here. The sentence literally translates to "Here text four".

Does the word текст mean the exact same thing as "text" in English?

Yes, текст is a cognate (a word that sounds similar and means the same thing across languages). Because it ends in a consonant, it is a masculine noun in Russian.

How does the soft sign (ь) change the pronunciation of Здесь?

The ь at the very end has no sound of its own, but it tells you to pronounce the с before it as a "soft" consonant. You do this by pressing the middle of your tongue up toward the roof of your mouth, making it sound a bit closer to the "s" in "see" rather than the hard "s" in "bus".