Tax due needs to be paid by April 15, 2024.
If you have federal tax due you can pay by mailing your payment with the 1040V voucher, (which has the address printed on it, having the payment taken out of a designated bank account, or you can pay directly on the IRS website.
https://ttlc.intuit.com/community/tax-payments/help/how-can-i-pay-my-federal-taxes/00/26212
To apply for a payment plan with the IRS
Apply Online for a Payment Plan
You must pay your state tax due using the state’s preferred method of receiving payment. For most states that will be by making a payment to the state’s own tax website, or by mailing a check or money order.
https://ttlc.intuit.com/questions/1901670-how-do-i-contact-my-state-department-of-revenue
Taxes owed for tax year 2023 are due and payable on April 15,2024.
You can set up a payment plan using this IRS website - https://www.irs.gov/payments/online-payment-agreement-application
April 15th is the deadline to pay your taxes without interest or penalty. If you are unable to pay your taxes in full, you should still file by April 15th, but you can apply for a payment plan from the IRS. If you set up a payment plan, interest and penalties still do accrue for any day it is not paid after April 15th.
You can file an extension to file your return. This does not give you an extension of time to pay, just an extension of time to file. Your payment would still be due on April 15th.