Paid around $4000 for school fee, but around $50 is shown as credit for LifetimeLearningax in turbotax.Is it not 20% of the first $10000 which is around $800 in mycase

The amount of the credit is 20 percent of the first $10,000 of qualified education expenses or a maximum of $2,000 per return. The LLC is not refundable. So, you can use the credit to pay any tax you owe but you won’t receive any of the credit back as a refund.

For TY2018, the amount of your LLC is gradually reduced (phased out) if your MAGI is between $57,000 and $67,000 ($114,000 and $134,000 if you file a joint return).

https://www.irs.gov/credits-deductions/individuals/llc

Where can i find the percentage of phase out

<a rel="nofollow" target="_blank" href="https://www.irs.gov/pub/irs-pdf/f8863.pdf">https://www.irs.gov/pub/irs-pdf/f8863.pdf</a>