It is text, short and simple. But it is text that is standardized so all computers everywhere understand it. Look at your keyboard. There are actually 128 of them in all. Now it gets loopy.
Computers deal with numbers.
Yes, you see little letters, but the computer doesn't. An extra digit is often added as a check to see if the other seven are correct. You may well ask. I told you, this gets loopy. Those 128 groupings of ones and zeros represent text, period.