How hard is it too build a fence wall between two neighbors?

Labor intensive!

Possible, but easy it isn't. Digging holes for fence posts is hard work. I highly recommend hiring out this portion of the job.

First you have to find out what the local municipality allows. If not a replacement of an existing fence, you might need the county surveyor to come out to decide where it is to be placed.

https://www.homedepot.com/c/how_to_build_a_fence_HT_PG_BM

https://m.wikihow.com/Build-a-Wood-Fence

https://www.familyhandyman.com/garden-structures/fences/build-a-privacy-fence/view-all/

Digging the post holes deep enough and big enough is labor intense, then mixing and filling the holes with concrete. Need to stabilize the posts to hold them vertical and level until concrete sets up. The first thing you'll have to do is order a survey to mark property line unless your neighbor agrees with you. You may also have to have a permit.

It's very hard--because if you get the lot lines wrong, you'll have to rip out the fence and do it over, or be embroiled in a battle with your neighbor. At the very least, consult your survey, or have a surveyor mark the lot lines for you before you proceed.

Putting up a fence might raise your property taxes. Check with your county assessor before going to the expense and trouble of building. Also if you have the time and permission of your neighbor, you could plant a row of hedge bushes or trees instead.

Thanks to all your answers I dug the holes did the Cement put up the fence myself thank you so much for your help