Every person who is seeking to create a Doc&Do account should create an individual account type. It's personal to them and they can create their business entity right from this account.
For businesses with partners, the use of the "organization" account type may be more appropriate.
The reason is that each account is allocated a set number of resources and those accounts could have one or more entities. So a sole business owner does not have any conflicts with using the resources for multiple businesses as they are paying for the account themselves anyway. A multiple owner business who pays for those resources most likely will want ALL of their resources available to their business, so the "organization" account type was created for that purpose.
Anybody could create an "organization" account type for their business if they so choose. However, the system will provide you the most value when you do all your work as yourself. The system tracks who does what, and invitations are generally made to a person from a business, not the other way around.
As a side note, after you create a business account, you will add yourself (your personal username as an "admin"). Once you have the business (organization) account setup, you have selected the plan with the number of resources you need, and you have added yourself as an Admin, you can logout of the business account and login as yourself (your personal username). Then select the Entity you created with the business account and you can do all your work as yourself. It's the optimal way for you to achieve the best structure and accountability.