ICANN's tax residency certificate and other tax related documents can be found here.
A quotation for the gTLD evaluation fee can be found here. If your organization's internal control process necessitates a consolidated quotation (pro forma) due to timing or other considerations before submitting applications for multiple TLDs, please email globalsupport@icann.org and indicate the number of TLDs requested.
If you need further documentation to facilitate payment, please reach out to globalsupport@icann.org.