That is not how patches work. The pnach format is as follows:
Code:
patch=[mode],[cpu],[address],extended,[value]
A practical example:
Code:
patch=1,EE,20289db0,extended,24040000
[mode] is the method of which the patch is applied. 0 is only once at boot, 1 is every CPU cycle.
[cpu] is the PS2 CPU whose memory space should be modified. I have yet to see the IOP be patched, as it really only runs input/output devices and has little impact on gameplay in most cases.
[address] is the memory address to write to. This is a four byte, 32 bit integer in hexadecimal. Note since the PS2 memory space is not large enough to use the fourth, most significant byte, this byte is ignored when mapping to PS2 memory. Instead, the pnach format uses the leading digit to specify how many bytes to write at the address. Leading the address with 0 will only write the least significant byte, leading with 1 will write the two least significant bytes, and leading with 2 (as in my example) will write all four bytes.
[value] is the new contents for the above address. This is also a four byte, 32 bit integer in hexadecimal.
When patching, you are replacing arbitrary bytes of data with new ones. There is no magical "make this text please" option. If you are trying to replace string literals, you will need to convert your replacement text to the raw bytes that correspond to the characters in the text. A quick Google search is all it takes to find an ASCII table.