Is there a website for tax preparers to obtain information on the amount of stimulas money clients received?

[Just-Lisa-Now-]

Nope, the client needs to find this for you. 

Unless you want to go through the rigmarole of submitting a 2848 or 8821 to access their transcript yourself.

Be sure you charge enough to cover the time and effort involved from you.

[IRonMaN]

But the good news is your clients would have received a written notice along with the first payments and the notices for the second payments are now trickling in, so I'm sure all of your clients will bring those documents in with them.

[qbteachmt]

Stimulus info can be found at these links:

https://www.irs.gov/payments/view-your-tax-account

https://www.irs.gov/coronavirus/economic-impact-payment-information-center

https://www.irs.gov/coronavirus/get-my-payment

https://www.irs.gov/coronavirus/second-eip-faqs

https://turbotax.intuit.com/stimulus-check/

https://ttlc.intuit.com/community/articles/community-news-announcements/second-stimulus-resources/05...
And: "The IRS said you can check the status of your second stimulus payment at IRS.gov/GetMyPayment (GMP).

If GMP reflects a direct deposit date and partial account information, then your payment is deposited there. If the payment was mailed, it may take up to three or four weeks to receive the payment. Watch your mail carefully and be sure not to throw out your payment.
If GMP shows “Payment Status #2 – Not Available,” then you will not receive a second stimulus check and instead you need to claim the Recovery Rebate Credit on your 2020 Tax Return."

Here's a link to the image for seeing an account transcript image example, which you can get for them or they can get for themselves:

https://www.irsmind.com/irs-notices/irs-transcripts-now-provide-stimulus-payment-information/

Good luck.