What info do I need in a form where people can pay/donate with Bitcoin?
This model fundamentally won't work.

In the case of a credit card transaction, the funds are actually held by a third party: the customer's bank.  You collect information from the customer (their card number, etc) and present it to the bank (via the Visa network or similar), to convince them that their customer has authorized the transaction.  The bank then transfers the funds to you.

With Bitcoin, it is very different.  The funds are held by the customer herself.  There is nobody who can perform the transfer except her (that's what keeps her funds secure!).  You cannot do it unilaterally on her behalf, and there is no bank holding the funds who can do it.

Strictly speaking, the "necessary information" to execute a transfer is the customer's private key.  But the customer is the only one who has it, and she is not going to share it with you (don't even ask).  So she has to execute the transfer herself.

The only way to collect a payment via Bitcoin is to give an address to the customer and wait for her to make a transfer to that address, signed with her own private key via her own wallet software.  You can have a third-party processor like Coinbase handle that for you, but it doesn't change the fact that the customer actually has to do something besides giving you information.