Yes, you can invest in as many mutual funds as your want within the same fund house.
You can even invest more in your existing folios/mutual funds by following these steps:
1. Go to 'Dashboard' by pressing the button below
2. Select the fund in which you want to invest more
3. Click on 'INVEST MORE'
4. Choose 'MONTHLY SIP' or 'ONE-TIME'
5. Enter the amount
6. Make the payment to proceed
Note: For monthly SIP, it is best to have an approved AutoPay mandate for automatic monthly payments.