Thanks for the resolving my doubt. Now tell me what are the documents needed for the procedure of increasing the credit limit on my DCB card?

I have to travel from my hometown to Pune on a monthly basis because I work there now. I use my icici Rubyx Credit Card primarily to purchase tickets, and I spend 12k - 15k a month. Do you have any suggestions for cards that offer the best rewards?

I have an hdfc dcb card, when I click on card details in my mobile app on my android phone, in front of the current limit, then there is a link called:  increase limit. When I clicked on the link after confirming then, I got a call to increase the limit. Right now I cancelled the request.
My question is this: is this link with the increase limit visible for me only, or is it present in the app for everyone? Can I increase my limit without doing any cibil inquiries?

In December last year, we took a loan (75 lakhs with interest of 8.5% for 30 years) to buy a house. I and my wife both are government employees. My wife, mother and I are the names on the loan, but only I am paying the monthly installment of Rs. 69,300. A new loan has been taken by my mother but she will be retiring soon.
So tell me, what is the highest tax savings on house loan that we get? Should I opt for different banks to increase our savings?
And if I am taking any health insurance, is my spouse eligible to receive tax benefits?