Every character your keyboard produces is stored as a number under a text encoding — this tool assumes UTF-8 — and that number can be displayed in different bases: hexadecimal (base 16, used in color codes and memory addresses), binary (base 2, the raw bits), decimal (base 10, the number itself), or octal (base 8, still seen in Unix file permissions). Editing any field re-derives all the others live from the same underlying byte values.
UTF-8 encodes ASCII characters in a single byte but uses two, three, or four bytes for characters outside that range — accented letters, emoji, and non-Latin scripts included — so their hex or binary representation runs proportionally longer.
They're the same value in different bases — 01000001 in binary equals 65 in decimal, which happens to be the ASCII/UTF-8 code point for the capital letter "A".
A full sentence works fine — each character is converted independently and the results are shown space- or byte-separated in each format, in the order they appear in the input.