You can enter bytes in any of the following forms:

Embedded
Raw ASCII text with UTF-8 encoded characters represented by backslash escapes:
Freeform numeric
Space separated bytes in one or more of the following numeric forms:
Hexadecimal
A hex dump. Bytes are extracted two characters at a time, with all whitespace ignored, e.g. 123456789ABCDE.
Binary
Space-separated list of binary numbers, e.g. 01010101 10101010 11110000
UTF-8 interpreted as Windows-1252
Raw UTF-8 encoded text, but interpreted as Windows-1252. For example, if your source viewer only supports Windows-1252, but the page is encoded as UTF-8, you can select text from your source viewer, paste it here, and see what the characters really are.