I'd just like to know if anybody can create an address and if it is accepted the developers, then it would be used? Like, can a person create an address and use it for himself alone, or does the address have to be included into the Bitcoin code or something to be compactable? How does it work?
First of all, the developers don't accept or reject Bitcoin addresses; the network does, but the network does not recognise the address directly. It recognises the type of script your Bitcoin is locked on. Your address is just encoded in a format in either be Bech32 or base58, which are usually converted to script hash.
You should check
https://learnmeabitcoin.com/technical/transaction/output/scriptpubkey, you can create any of the locking scripts and have it encoded to any of the formats, base58 or bech32.
It you generate an adress using the regular wallets we use yes it’s unique to you alone, but let me assume you don’t want wallet to generate keys or addresses for you and you want to do the Mathematical part yourself it is still possible, but first you have to
Randomly generate a private key outside computer environment and then subsequently generate your own address. But all this must have to be in line with the consensus of the scripts type of the network,
This is not what I meant.
You know how there are different types of addresses like P2SH, P2PKH, P2WPKH and all of them have their own prefix and total number of characters. Now there is a new P2MR address being proposed that it is a quantum resistant address, so if for example a person can create such an address (P.S. I don't mean generate), I mean to create a new address type like P2MR, can he use it on his own or does the network need to made aware of it before it can be used. And if the network needs to be made aware of it, what is done that makes it compactable before it can receive and send Bitcoin.
The address is just a proposal, and it is not recognised yet on the network. For it to be usable and compatible, there is going to be a soft fork, like the way Segwit was created back in 2017. If it becomes a standard, anyone can create it and use it.
If you create any locking script that is not standard and you lock Bitcoin on it, your Bitcoin will be lost forever.