I want to replace my carpeting with a wood floor.
The finished look we desire would mean laying the floor parallel with
the joists. House is 6 yrs old
The floor consists of engineered 12 inch truss joists stamped TJI PRO
350 most are 12 to 14 inches on center
with 3/4 inch plywood ring nailed and glued to joists.

I would like to keep the wood floor near the same level as the ceramic
tiled kitchen and entry way.
Tile surface is about 7/8" above subfloor
1. Can I put down a wood floor consisting of either 3/4" wood flooring or
engineered wood on the 3/4" subfloor or
2. Will I have to add 1/2" plywood (using screws?)over existing 3/4" plywood to strengthen the subfloor? Then I will use 1/2" engineered flooring.

It's recommended to have a total of 1 1/4" subfloor when laying parallel to the joists. So I would go with the extra 1/2" plywood.
Personally, I would probably go across the joists no matter what it looks like to avoid the hassle of extra subfloor and reducers. But that's just me.

The recommendation for adding extra underlayment/plywood is to STIFFEN the existing subfloor up. NOFMA's minimum recommendation for 3/4" SOLID strip flooring is 5/8" plywood over joists spaced 16" OC. AND to run the flooring at right angles to the joists. The reason for that is if one were to run the flooring parallel, you could have flex between the joists, which could cause problems. If your existing subfloor is very stiff and has no deflection between the joists, you could probably get away with running the wood parallel to the floor trusses/joists. With the joists/trusses spaced 12" OC and 3/4" plywood subflooring, you existing subfloor MAY be stiff enough or it may NOT. I cannot tell from here. Another option would be to install blocking between the trusses but being that they are engineered trusses and not solid lumber joists, attaching them to the trusses would be difficult and probably not work.