Technically you can't in all but a few states. To form a group under the regulations of virtually all states you have to have an employer-employee relationship which at a minimum requires two people, the employer and at least one common law employee (generally a W2 status employee).
Colorado and Delaware do appear to be states that make provisions for a self-employed person to purchase health insurance on a group contract basis.
This is one of the issues the Affordable Care Act essentially dealt with beginning on January 1, 2014 when it's provisions eliminated pre-existing condition exclusions and being declined for coverage in the individual and group marketplaces. So, other than the fact that the open enrollment season concluded on March 31st, 2014 there is now no legal prohibition preventing a self-employed person from getting individual health insurance. This does not mean, however, that states have changed their individual laws regarding eligibility for group contracts and to the best of my knowledge no states have changed their policies in this regard.
There are still a few industry association group health plans in existence but they have become increasingly rare over the years. For most self-employed persons reading this answer your best option and generally your only option will be to purchase individual health insurance.
Colorado and Delaware do appear to be states that make provisions for a self-employed person to purchase health insurance on a group contract basis.
This is one of the issues the Affordable Care Act essentially dealt with beginning on January 1, 2014 when it's provisions eliminated pre-existing condition exclusions and being declined for coverage in the individual and group marketplaces. So, other than the fact that the open enrollment season concluded on March 31st, 2014 there is now no legal prohibition preventing a self-employed person from getting individual health insurance. This does not mean, however, that states have changed their individual laws regarding eligibility for group contracts and to the best of my knowledge no states have changed their policies in this regard.
There are still a few industry association group health plans in existence but they have become increasingly rare over the years. For most self-employed persons reading this answer your best option and generally your only option will be to purchase individual health insurance.