If you wish, though it may not really be necessary, you can pay both federal and state estimated taxes online:
FEDERAL
https://www.irs.gov/payments or https://www.eftps.gov/eftps/direct/EftpsHome.page
CALIFORNIA
https://www.ftb.ca.gov/pay/index.html or https://webapp.ftb.ca.gov/WebPay/Login.aspx
and you can choose to pay all the taxes at once or spread the taxes out over the remaining two quarters.
But as I suggested in the open sentence, it might not really be necessary to make any payment at all until you file your income tax return. Although the US and California income tax systems are styled as "pay as you go" which suggest that anytime you receive income you should be remitting taxes, that's not exactly how it works. It's perfectly OK to owe a lot of taxes when you file your income tax return though you do want to pay enough to avoid "underpayment" penalties.
Most taxpayers will avoid being underpaid if they:
1)owe less than $1,000 in tax after subtracting their taxes WITHHELD and available tax credits,
OR
2)if they paid at least the lesser of
a)90% of the tax for the current year, or
b)100% of the tax shown on the return for the prior year. (If last year's return shows AGI over $150K (for married filing jointly) then change that "100%" figure to "110%.)
So if you have a job and can make your withholdings paid in 2019 amount to 100%/110% of last year's tax liability you may choose not to pay estimated taxes. You might still write a big check to send in with your tax return, but you won't be assessed penalties.
