How load sharing can be done in AC mains and inverter?
The proper way to do this is:

Use a grid-tie inverter. This is one that synchronises the AC from the inverter with the AC on the mains.
The grid tie inverter will have safety features to ensure that if mains fails that the inverter will not put power out on the grid and possibly electrocute a lineman.
Now you have two feeds into your house. The loads will consume all the available power from the inverter and the mains will make up the rest.

If your inverter is not a grid-tie type then you cannot use it in this manner. You will usually have to notify the utility company that you wish to do this and may be subject to inspection to ensure that you comply with local regulations.
Note, I have given some terminology here to get you started on your own research. I will not be designing a system for you or having a conversation about it.