It is still illegal to use or possess marijuana under Texas law — and has been since 1931. What changed in 2019 is that hemp is considered different from marijuana.
Since the law change, prosecutors and state crime labs have dropped hundreds of pending marijuana charges and declined to pursue new ones because they don’t have the resources to detect a substance’s precise THC content, arguably keeping them from the evidence they need to prove in court if a cannabis substance is illegal.
Gov. Greg Abbott and other state officials insisted that the bill didn’t decriminalize marijuana and that the prosecutors don’t understand the new law. Still, marijuana prosecutions in Texas plummeted by more than half in the six months after the law was enacted, according to the data from the Texas Office of Court Administration.
Bottom line - you're less likely to go to jail for possession, but smoking weed is still technically illegal.