Thanks for your query.Based on the facts that you have posted it appears that your 6 years old daughter has gross hematuria
and burning while passing urine.
The gross hematuria in child age group is mostly due to Acute Glomerulonephritis
or Glomerulopathy due to various causes .
Please consult qualified Nephrologist
for clinical assessment and get detail investigations done under his guidance to find out the cause of hematuria..
Thanks and Regards.