The Team Rocket uniform that your Player Character temporarily wears is only available in Pokémon HeartGold and SoulSilver. You will need to defeat 7 out of the 8 Gym Leaders in the Johto region and then head to the Radio Tower in Goldenrod City and talk to the Team Rocket Grunt that is blocking your way upstairs. Now you can go into the Underground Tunnel via the North entrance in Goldenrod City in order to get put into a Team Rocket uniform.
You have to defeat the first 7 Gym Leaders in Johto, you'll receive a call on your Pokégear after you do all of that saying there's an issue with the radio waves. You head to the Goldenrod City Radio Tower and you'll find that as soon as you go in there, it's crawling with Team Rocket Grunts. If you talk to the Grunt blocking the staircase, he'll tell you he's under orders to not allow anyone up the stairs unless they're wearing their uniform so you have to go into the Underground Tunnel which is nearby and head up to the north part of the Underground Tunnel and talk to the Team Rocket Grunt there. He'll put you inside a Team Rocket uniform however this is only a temporary thing.
You need to go to the underground basement and find a rocket member next to a camera. He will give you some rocket clothes and you can go up there. But once you go there, your rival blows your cover and you have to fight a rocket
Go to the Underground Tunnel, talk to the Team Rocket Grunt, and he'll give you a uniform. Then go back to the Tower.
okay well my memory's bad but this is what I remember, go to the northern part of the underground tunnel in Goldenrod city and talk to the Rocket Grunt that is standing near a door. Talk to him, and he will give you a Team rocket outfit. Go to the radio tower and the Rocket grunt will let you in, until your rival comes and ACTUALLY sticks up for the towns people. (Guys, c'mon, I was Shocked. This guy isn't supposed to care, at all). But he reveals your identity then runs away. Defeat everyone you can get to (Because it's easier that way), until you get to one of the rocket executives who is mimicing the radio tower manager person. He'll give you a key to unlock a door in the southern part of the underground tunnel in Goldenrod City. Beat everyone in there. And also be prepeared because you'll run into your rival again (yay, fuuuun) and I'm pretty sure he'll battle you. If not then my bad. Talk to the REAL manager guy and he'll give you a key to unlock the door in the Radio Tower so you can battle all the other super fun Team rocket Executives. And don't stress they're not very hard, Most of them have 3 Pokemon Max. --- Sorry it's so long ---
You go to the building to the left of the guy that changes your Pokemon's nickname (who lives in a purple tent in the upper part of town). Go inside the building and down the stairs. Talk to man who takes pictures of your Pokemon and he will change you into a team rocket uniform.
Go to the Underground Tunnel in Goldenrod City. There is a Team Rocket Grunt there who will give you a uniform.
the underground tunnel in goldenrod
you have to go back to where the photographer in the underground tunnel is and a team rocket grunt shall give it for you to wear
in the underground tunnel in goldenrod city
go to goldenrod city and go to the underground tunnel a look around and there is a team rocket grunt there he will give it to you
One you cant keep the outfit. Two its in the underground tunnel in goldenrod city. And three you get to take a picture with your Pokemon party wearing the outfit.
To get the team rocket uniform, to get in the radio tower. all you have to do is talk to the rocket in the lobby of the tower, he wont let you in until you have a uniform. So go to the underground tunnel and near the photo studio there will be a rocket who will give you one!
Goldenrod's Tunnel
It's in Goldenrod City to the left of the Game Corner or to the left of the Name Raters house.
You must go to the North Underground Tunnel in Goldenrod City, and talk to the man in the Team Rocket Uniform near the counter. He will think you are a newcomer, and will give you the shirt.
you have to go to the underground where the dude takes pictures of you in a Team Rocket uniform. There will be a Team Rocket grunt who is looking for recruits. He will give you a uniform.
When going through the Team Rocket scenario in Soul Silver or Heart Gold in Goldenrod city, you can go into a tunnel and look for the man in a team rocket outfit. He will give you the uniform.