Hi
Is there a kit that I can purchase with instructions for building autonomous drone?
There would be a kit probably but I think the best way is to read the wiki and understand and then build it.
Many kits/ combos I have seen use the cheapest type of stuff and they are to be avoided.
But, if you want to do the kit way, you absolutely can
This link has some ready to fly vehicles. You could explore these. Just ensure that it has a good h743 fc and other things meet your demands like size, power, etx
Don’t buy anything on this list Hardware to Avoid
There are very few kits around. Many on that Wiki entry list are no longer available, commercial drones that are very expensive, or some niche product. The Hexsoon and HolyBro craft are popular if you can find them as ARF kits.
But, just do what @Ishitbh suggested and read the Arducopter documentation and read the forums and put your own Bill of Materials together and get to construction.
There are comprehensive build Blogs here on the forum for 5" and 7" craft from an Arducopter developer that are excellent.
If it’s your first build and you do not have prior experience with ardupilot, put your bom in this thread before buying them since many beginners (like me) make a lot of mistakes buying parts.