If you determine your products/services are taxable and you have nexus, then you must register, begin charging and collecting sales tax and file and remit returns to all the states and jurisdictions in which you have nexus. That is unless an exemption applies.
An exemption is an exception that eliminates the need to charge and collect sales tax on an otherwise taxable transaction. Certain products and services may be non-taxable and not require an exemption certificate.
Source: taxconnex.com
