You asked how people come to determine their own type?...Here's how I did mine.
I, as an EII, I can look a lot like LII, because I can have/make systems for doing things but unlike Ti, I am not as critical/analytical/justice focused, much more humanitarian and because of Fi, I am much more moralistic and entirely merciful.
I choose my type by objective VI method first, I gave people independent of one another to type me, if they got it wrong, all three that claimed to be experts in the field, then I was going to pursue something else, but they all got it right. So, then I kept a year long journal of me, wrote everything about myself and then had family and friends tell me what they thought about me and kept that in another journal; when I put the picture together it was EII.
I looked at my weakness first, thought of all the things I couldn't do and didn't want to do...it all pointed to Te.
Then I looked at my behavior that all pointed to Se PoLR
I also looked at my values.
My inventive nature and my humanitarian values...I have always, from early childhood, took up causes to help people, volunteer in places were people needed emotional help...like synagogues for survivors of the holocaust when I was a teenager and many of the other kids were busy partying...