Do we have to pay the 1040-ES Payment in 4 installments? Can we pay all at once?

[VolvoGirl]

Yes.  But do you understand the 1040ES are not for your current tax due?  They are Estimated payments for NEXT year so you don't owe so much again.  They are optional to pay.

You have to pay your current 2018 tax due by April 15.  You will have a 1040V for that.

[Carl]

Assuming you completed your 2018 taxes, if you'll look at the forms you'll see that the 1040-ES forms are for tax year 2019 (twenty nineteen). These are printed only if you have a tax liability due on the 2018 return, or if you are reporting self-employment income, or if you made estimated 2018 tax payments last year. Pay attention to the due dates on those 2019 Form 1040-ES forms.
Now you do not have to pay quarterly taxes if you don't want to. But be aware of the following:

If at tax filing time if what you owe the IRS is more than $1000 or more than 10% of your total tax liability (whichever is *higher*) then you will be assessed an underpayment and/or under withholding penalty. So if you "think" that could happen when you file your 2019 taxes next year, you may want to at least consider paying quarterly taxes. But again, you don't absolutely have to.