First you need the most important photos to start.
– Portrait photo (front and side)
– Full body photo (front and side)
These photos are only for application to the agencies and should therefore be as natural as possible. Photoshop or image effects. You can take the photos with your smartphone or better: Ask a friend who is a hobby photograph to shoot with you. He should use a portrait lens if he has one. If you have film recordings, send them along. If you have several film recordings, cut your personal show reel from it for a maximum of 90 seconds.
Every agency always has a few extra requests. So that you have suitable application photos for all cases, it is worth taking a whole range of different photos during the shoot. That means you get yourself different clothes like: business, business casual and casual. (A trick if you have no money: you can buy clothes in the shop, shoot and then bring the clothes back cleanly.)
Try out different facial expressions: serious, light smile without teeth, bright smile with teeth, etc.
Location is not so important, because the background is mostly out of focus anyway. It is only important that the lighting is good – but your photographer must be familiar with that.
Resize your Images to fit a maximum file size of 500kb. You upload your photos to your dropbox, as some agencies don’t like it when you email them huge photos. They just want the filelink to your Dropbox.
Then you should write down your measurements for your Sed Card: Head circumference, chest circumference, hip waist, size, shoe size, weight, clothing size, collar size, hair color, tatoos, scars, etc.
Then you can get started: You click on the websites of the agencies and send them your stuff. Most agencies have forms to fill out. Take a look at this how-to : https://paragonmodels.com/de/model-werden/bewerbung.html
In the appendix I sent you a preselection of agencies. Googling that is not an art. Applying to all of them is the main job and takes time.
There is a rule of thumb for the success rate: 42 times no, 1 time yes. But it can also be better for you. This is because every agency shoots different faces and different clients and other things. This is not meant personally, their are just searching for other profiles.
Few can live from modeling alone, most do something else. See it as fun.