The certificate in form 16A is the certificate issued by the deductor of the TDS deducted under different sections of the Income Tax Act, other than the salary section of 192.
26AS is the tax credit statement comprising of all the deductions of TDS and TCS from all the deductors.
16As are generated once the TDS returns are filed and the certificate numbers are generated from the TRACES portal.
26AS generated at the TRACES portal collaborates all the 16As from different deductors at the backend and issues the combined tax credit statements, i.e., 26AS.
16As are based on the data uploaded by the deductor before the revision of the TDS return.
If the deductor chooses to revise TDS return, then the 26AS gets revised and takes into consideration the impact of the revisions.