Hex to ASCII
Capital A is 0x41 and lowercase a is 0x61 — exactly 32 apart, which is a single bit. That is why toggling case used to be a bitwise OR with 0x20. Space is 0x20, digit zero is 0x30, and the printable range runs 0x20 to 0x7E. Anything above 0x7F is outside ASCII proper and belongs to Unicode.
Each pair of hex digits is one byte, and each byte is a character code. 48 65 6C 6C 6F decodes to "Hello". Codes above 7F are outside ASCII and are read as Unicode code points here.
How to decode hex to text
Strictly, ASCII covers only codes 0 to 127, and everything above that depends on an encoding. This tool treats each value as a Unicode code point, which matches UTF-32 and agrees with ASCII for the first 128 characters. If you are decoding UTF-8 bytes — where a single character can span two to four bytes — the byte-by-byte reading will produce mojibake, and you want a UTF-8 decoder rather than a character-code one.
Questions
Capital H. The full sequence 48 65 6C 6C 6F spells Hello.