My employer did not deduct CASDI from my taxes for 2021. Where do I enter CASDI for California tax return. CASDI is reported on Box 14 on W2. Any help is appreciated.

You cannot pay your own CASDI.  Your employer is required to withhold from your paycheck or provide voluntary coverage (if it is not on your W2 Box 14 this is most likely the case).  If you are not sure, you should ask or you can contact  Ask EDD.

Sometimes they put it in box 19.  Is it there?  Move it to box 14,  

And CASDI does not go on your California return at all.  Unless you had 2 or more employers then you can get the excess back.  And it is more than 1%

The SDI Withholding Rate for 2021 is 1.2 percent. The SDI taxable wage limit is $128,298 per employee for calendar year 2021.  The maximum to withhold for each employee is $1,539.58.  If one employer took out more you have to get it back from the employer.  So if box 14 (or 19) is more only enter the max for box 14 on that W2.

For 2021 the maximum tax is $1,549.58 per employee, per year ($128,298 x .012).

See SDI rate

Rates, Withholding Schedules, and Meals and Lodging Values

It was due to error by HR that CASDI was not withheld. I owe approx. $850 for CASDI. I was expecting that Turbo Tax will report it as error but it did not. Now how do I pay this money. The other option is to ask my employer to amend W-2 which takes time. I am surprised that Turbo Tax did not find any errors in state tax return.

Nothing is in Box 14 or 19. My employer did not deduct at all due to some error by HR. Now I owe $852. How do I pay this amount?

Sorry we don't know.  You have to ask California.  Maybe you don't need to pay it back.  Is your employer taking it out now?