Only donations made to fundraisers that are set up by legally registered non-profits (NGOs) or charities may be considered eligible for donors to claim as a tax deduction. Look for a note '80G tax benefits for INR donations' below the 'Donate Now' button on the fundraiser. You can also filter for fundraisers with tax benefits on the listing page here
Milaap is not an NGO and is only a custodian of funds hence can not provide tax exemption.
If you have donated to a fundraiser that provides tax exemption, you can download the tax receipt from your dashboard. To do so, you will have to log in to your Milaap account using your email ID or registered mobile number and then visit your dashboard to download tax receipts.