Query related to BoB structure change fy24-25

Can anyone guide me on the below query ? I've selected old regime so as per the old regime i can get exemption upto 3000 per month on food card allowance. So, if I change BoB with 3000 amount in food allowance. Will that 3000 amount be credited in my salary instead of credited to the food card if I don't have food card? And for LTA can I specify any amount to get rid of deduction from TAX or do I need to upload any proof ?