A blue line goes up and down my screen

i was in the accessibility settings and i cant remember what i press but now a blue line is going up and down my phone and i cant even get access to my screen, when i touch the screen it makes a sound. please i need help

crwdns2934089:0crwdne2934089:0 crwdns2934093:0crwdne2934093:0

crwdns2934109:0crwdne2934109:0

crwdns2889612:0crwdne2889612:0 0
crwdns2934285:0crwdne2934285:0