Interviewer is trying to find out what school credentials you have. If you have no formal school qualifications but have a lot of experience, you might say:
☛ I didn't get formal school training for this job but I have (number) of years of experience in the field. I'm willing to learn new skills or go to school to get further training if I am offered the job. I learn quickly and I like to keep upgrading my skills.
If you have just completed a training course but have little work experience, you might say:
☛ I took a one year training program in (name of program) at (name of school) which is related to the job I'm applying for. I look forward to working in the field and putting into practice what I learned. I don't have a lot of work experience in this area but I learn quickly. I know you will be happy with my work.