I installed the default version of the Security + mod and the characters' clothes looked like this ... jajaja does anyone know how to solve it? on the other hand, the cars and the agency are normal, along with the callouts.

This would seem to be the models or the agency config is missing, make sure you installed everything exactly as the instructions said to. Also try a youtube tutorial, that can help make sure you did it exactly right.
As always install into your mods folder if you're not already

I think i'm install alright,I still have the problem. ;-; 

Make sure you install these as well, they are all required for it to work properly.

Spoiler

 

Those instructions you attached are just for the agency configurations, make sure you have security+ itself installed as well if you want to use it

I installed as you said these 3 uniforms, thanks for recommending them are really good, but the problem is still installing, I tried to remove the folder "outfit gru.xml" but even so, this ugly outfit persisted, about security + me I have it installed right, so much that I already managed to make some callouts, I think the mod itself is out of date or the modder has abandoned, at least my game does not crash because of that, it is also worth mentioning that the Paramedics and Firefighters called by the ultimate backups are also wearing funny clothes, I tried to post on the support of the mod itself but it seems that I did not get answers, I hope your help but I think I will have to uninstall kkkk.

I know the last thing you'll want is even more to install but for first responders to show up in the right uniform you'll want this https://www.lcpdfr.com/downloads/gta5mods/datafile/22434-lspdfr-backup-adds-eup-uniforms-and-other-options-to-ultimate-backup/

This may also fix your outfits problem for G6 if you install in this order:
File I just sent
The file "Gruppe Sechs Corporate Security [AGENCY]", you'll just want to install it again

If none of that works you can try installing this, it comes with uniforms https://www.gta5-mods.com/vehicles/the-security-pack-add-on
 

i tried to install this file,but my game it got worse, it bugged the uniforms of others even more, unfortunately it didn't work either, this "The Security pack" I tried to install but I couldn't, because I never installed it by this method, I didn't understand this part that is saying by, besides not being fluent in English, never having done it, if you can explain in more detail what you have to do, I thank you, I already have Open IV, add-on all this already done.

In your vehicles.meta find the entries for the models Dilettante2 and Stockade, remove those entries and put the 2 in the readme in their place.
Here is a vehicles.meta with only that edit done: vehicles.meta I did not do the typical tint removal for police4, sheriff2, fbi2 and pranger and I did not change any handling, just the entries that the readme says to edit. If you want to use this meta just replace the one you have in your mods folder

If you have EUP and all the configurations to go with it installed already I don't know what else you can do. The only other thing I can think of is make sure they all got installed in the correct order.

hello man, this is the last post here, I gave up on the mod, I tried to install this one by add-on, I think it came to install but it didn't work correctly, continue this gray uniform without a arm. I ended up removing everything from this mod " Gruppe Sechs (AGENCY) "because I think it is out of date, the last time the owner of the mod joined was in July 2019, I think he does not have support for the new dlc LSPDFR, so thank you for trying to help even though it was in vain kkkk, the police clothes are cool, and I reinstalled the ultimate backup of the Beljojo and the clothes of the Paramedics and Firefighters returned to normal, which leads me to believe that the problem is with the mod gruppe sechs, at least the calls are still possible, good game to you.

Well, that's the most that can be done then I guess. It would make sense that the agency configs are the problem with EUP having an update more recently
If you have EUP Serve and Rescue installed you can use EUP menu to access G6 uniforms, hopefully that can get you somewhat closer to what you wanted
EUP menu is found here