The Substantial Presence Test (SPT) is one of the residency determination methods used by the IRS in order to determine if you will be considered as a nonresident, dual status resident or resident for US tax purposes.
The other method is the Green Card Test.
Based on the Substantial Presence Test if you have enough days spent in the US which can be counted towards the SPT, you can be deemed as a resident for tax purposes.
Info: By filling out Step 1 Residency in your Sprintax account, the system will automatically determine your residency status for tax purposes based on the information provided and the IRS regulations.