Hi Namish
I looked up the technical specs here: https://www.asus.com/Laptops/For-Home/All-series/ASUS-E210/techspec/
From that it appears that there are either several choices for your primary storage or perhaps you have two drives.
64G eMMC
128G eMMC
256GB M.2 NVMe™ PCIe® 3.0 SSD
512GB M.2 NVMe™ PCIe® 3.0 SSD
128GB M.2 NVMe™ PCIe® 3.0 SSD
If you only have one, and it is one of the smaller two, then it is inadequate for sure.
If you have two, then you should have your operating system installed on the fastest drive, and your "My Documents", "Pictures" etc folders should be on the largest.
A USB 3.x external drive will also help, but you then need to always have it connected.
If you only have one internal drive, and if the laptop has room for another, then the best option is to get the biggest, fastest drive you can afford and added.
If you cannot add a second, then replacing the existing one would work, however this will require confirming that your warranty will still be valid, and it will also require a lot of messing about transferring the operating system and data you already have.
Unfortunately, I have no experience with Windows 11, so I can't even tell you how to tell what you have
All the best,
VS