The obvious answer is : as for any another work, no you can not practice without any qualifications or personal skills. Let's elaborate.
Technical skills/qualifications to be a hairdresser based on professional definitions
The name "hairdresser" overlaps three professions everyone of which corresponds to a specific type of license in all 50 states : Barber, Hairstylist, Cosmetologist.
These jobs, Barbers, hairstylists, and cosmetologists have a lot in common and theirs qualifications aim at providing hair and beauty services to enhance clients’ appearances.
But if we are seeking differences between these 3 professions, the Bureau of Labor provides relevant definitions :
" Barbers cut, trim, shampoo, and style hair, mostly for male clients. They also may fit hairpieces, perform facials, and offer facial shaving. Depending on the state in which they work, some barbers are licensed to color, bleach, and highlight hair and to offer permanent-wave services. Common tools include combs, scissors, straight razors, and clippers.
Hairstylists offer a wide range of hair services, such as shampooing, cutting, coloring, and styling. They often advise clients, both male and female, on how to care for their hair at home. Hairstylists also keep records of products and services provided to clients, such as hair color, shampoo, conditioner, and hair treatment used. Tools include hairbrushes, scissors, blow dryers, and curling and flat irons.
Cosmetologists provide scalp and facial treatments and makeup analysis. Some also clean and style wigs and hairpieces. In addition, most cosmetologists actively recommend professional hair care products or salon hair care products."
Based on that, we propose to sum up the skills to offer mobile barber services or stylist this way :
Analyze hair and scalp of a client to recommend treatment in case something wrong
Discuss hairstyle options with clients and provide advice regarding cutting and styling
Wash hair with appropriate products based on your diagnostic and client's preferences
Cut and style hair (including dry and application of hair products)
Color and lighten hair (full coloration or touch ups)
Education, Certifications, Licenses and Registrations
Every state in the US requires that barbers, hairstylists, and cosmetologists had followed and received a diploma or certification from a state-licensed beauty school. In these programs you will receive courses in hairstyling, barbering and other personal appearance services. Students who want to have their own beauty business may also take courses in sales and management.
Barbers, hairstylists, and cosmetologists must obtain a license in order to work in any state of the US. Requirements for a license vary by state, but generally, besides being graduated from a state-licensed beauty school, an applicant must fulfill the following criteria :
a minimum age of 16
take an exam that may include a written test, a practical test or an oral exam
justify of a practical experience under the supervision of an experienced professional or a master cosmetologist / barber
Besides technical skills and education, personal qualities
Of course hairstyling is all about aesthetics and relationships.
You should be committed and interested enough to keep up with the latest trends and maintain a good level of creativity.
You should also make a great deal of human relationships : able to listen to people to define what clients want, be patient, be friendly and entertaining.
It is really better if you are organized and precise. First concerning the management of time : you need to be able to organise your schedule effectively and then to keep up with it when you are servicing clients. Also you must be able to keeping business and inventory records, in order to order supplies in a timely manner.
Finally It is certainly important that you keep neat and trendy personal appearance, reflecting for your clients your ability to keep themselves trendy.