Whether you are required to collect sales tax on online marketing and web development services that you offer to clients in New York depends on a few factors, such as whether you have a physical presence in the state and whether the services you offer are subject to sales tax.
Generally, if you have a physical presence, such as a retail location, warehouse, or office, in New York, you are considered to have nexus in the state and are required to collect and remit sales tax on taxable products and services that you sell to customers in the state.
However, even if you don't have a physical presence in New York, you may still be required to collect sales tax if you meet certain threshold, such as making a certain number of transactions or dollar amount of sales in the state. This can vary from state to state and you should check the specific laws of New York.
The services that you offer may or may not be subject to sales tax, as this can depend on how the services are classified. In general, services are not subject to sales tax, but it is also possible that the state of New York could treat services as taxable, again, you should check the specific laws of New York.
I would recommend consulting a tax professional or checking the website of the New York Department of Taxation and Finance to determine whether you are required to collect sales tax on the services you offer to clients in New York and what your obligations are.
It is important to be aware of tax laws and regulations to make sure you are compliant and avoid any penalties from tax authorities.