Sweet pepper plants take on a bushy form. I give them plenty of elbow room of 18-24" apart give or take. If in rows I space them about the same, two to three feet apart. They do not require their soil to have a huge fertility. And perferr soil on the dryer side. That may not be a problem for you having a raised bed, which tends to heat up and dry out quicker. If the soil is dry down to 3-4" when tested with your green thumb..give them a deep drink.
I find that peppers give more of a fruit crop by not loving them so much...
I concur with Shadylane on the spacing. I do mine in 18" spaces apart and I also like to stake them. I have a lot of those 4 ft. long solid metal poles that look a bit like small diameter rebar used in concrete work. They have a triangular flat piece of metal welded on one end to help them stay firmly in the ground. I got them from Tractor Supply. I've found my pepper plants tend to fall over when they are getting full of fruit around mid summer.