I believe the there is no need to change the surname after marriage though it is advisable in some documents.
Marriage certficate says e.g. For example
Mr A B Sharma, son of Mr B C Sharma is married to Miss X Y Tripathi daughter of Y Z Tripathi on .......... at .... etc.
After marriage, wife may(and preferably shud) have another PAN CARD with the same PAN Number!! and another signature suggesting the husband's surname.
But there is no need (and also not advisable) to change any other document inculding passport, driving license etc.
What about name on original certs in education, awards, etc etc.
Just annex your marriage cer along in every place if you need a proof that female is married.
Previousbank account wud have the earlier pancard and any new bank account (if open using the husband's surname) after marriage may have new pancard.
Where ever signature is supplied ny the applicant thatsignature is valid. A person may have different signature or rather more than one type of signatures also and may have multiple PANcards with different signatures BUT with same PAN number on all (in english, devnagari or if yuo are NRI and residing japan e.g. and if you know japanese , you may have your own japanese kanji as your signature if you can!!)
Only problem faced by the female is that............, she has to remember where she signed as what fashion!! (Hence restrict to a very few places where you signed with surname of husband, just for the record. And continue elsewhere with your original name and signature. This is advisable. This is my opinion. Please suggest the cons of not chnaging the surname after marriage for my education)
To change the surname after marriage, there is an elaborate (but not necessarily lengthy) a step by step process. It shud also get published in the pereodical gazzette that your name and surname has been channged from 'Tripathi' to 'Sharma'.