It is necessary to upload provisional certificate in cat registration

dear aspirant,

THIS THE WHOLE PROCEDURE OF CAT REGISTRATION AS FOLLOWS;

• Go to the CAT website. Once the registration starts, there would be an option to apply online.
• Fill in your personal details in the CAT form online. They will also ask you to upload a passport size photograph and a scanned copy of your signature.
• Fill in your Class X, XII and graduation marks (till the semester for which marks are currently available). Be careful and fill in the correct marks, as they will be used during the shortlisting. You might also need to upload copies of your transcript
• Fill in your work experience details. I didn’t have work experience while applying so don’t know what all you need to fill in here, as I didn’t check this section.
• Select the IIMs and the programmes (PGDM, FABM, FPM and so on) within those IIMs to which you want to apply. Don’t miss out on any programme which is of interest to you, as the shortlists for any programme are only sent to those who selected that option in the form.
• Once you are done with all details, pay the requisite amount online.

BEST OF LUCK.

It is not compulsory. But here, I quote exact lines from IIM Calcutta page:
A candidate who has not received his/her graduation results at the time of registration will have to produce certificates and mark sheets in original together with the photocopies as soon as the respective University/Institute publishes the results, but NOT LATER THAN DECEMBER 31, 2019, failing which his/her registration as a student of IIM Calcutta will be automatically cancelled and he/she will be required to withdraw from the MBA forthwith. Any candidate who submits University Mark sheets which do not clearly indicate that he/she has passed the Bachelor’s Degree course or equivalent, and also submits Provisional Certificate from an affiliated College/Institute would, in addition, be required to produce an authorization certificate from the University stating that such an affiliated College/Institute is authorized/empowered to issue such a certificate on behalf of the University.