terrain tool spikes

im trying to make smooth terrain in unity but i keep getting these random spikes on the edges is there any way to get rid of these?

 

Need a screenshot or video to actally see whats going on...

 

its got really sharp edges and i cant figure out how to make it smoother is there a way for me to add more vertices?

 

You need higher resolution terrain or to have more terrain tiles. A terrain tile is a terrain that's high res but scaled smaller, and lots of them fit together.

Unity's tools will do this for you, read documentation. One big terrain will lead to spikes. There is not enough height map resolution for it.