Hi Nishat,
It’s helpful if you include OS details and Blender version.
Memory requirements for Blender is very dependent on the scene. There are a number of strategies one can use to lower memory usage. Like using lower res texture images, turning on “Adaptive Sampling”, reducing mesh density, etc… Also, upping the PC “Virtual” memory can help (this can benefit your system ram and GPU “virtual” ram also - at the expense of speed - but at least it runs). Device drivers might also be an issue. Make sure these are up to date. See a previous post on this which may help with that:
Also, if you are using Windows you can ensure all unnecessary apps in your “Startup” are disabled. Use the “Task Manager” > Startup tab to take a look at these. Right click to Disable. Just be careful not to disable anything vital. I’m assuming Windows 10 here though. Disable unneeded Services also can help (but again make sure it’s not a vital service). As Okidoki mentioned make sure you have ample space on your hard drive(s), especially if you are using any “caching” or simulation type of stuff.
Naturally more physical RAM or new video card with more VRAM would help immensely if that is a option. I know it’s very tricky getting one’s hands on new hardware at a reasonable price these days. So hopefully the above options work for you.
Cheers and stay safe!