We got married last September, how should we file? There is a discrepancy in income, he has a rental property and does help with mortgage but house is in my name only.

If you were legally married at the end of 2024 your filing choices are married filing jointly or married filing separately.

Married Filing Jointly is usually better, even if one spouse had little or no income. When you file a joint return, you and your spouse will get the married filing jointly standard deduction of $29,200 (+ $1550 for each spouse 65 or older)  for 2024. You are eligible for more credits including education credits, earned income credit, child and dependent care credit, and a larger income limit to receive the child tax credit. 

If you choose to file married filing separately, both spouses have to file the same way—either you both itemize or you both use standard deduction. Your tax rate will be higher than on a joint return.

 Some of the special rules for filing separately include: you cannot get earned income credit, education credits, adoption credits, or deductions for student loan interest. A higher percent of your Social Security benefits may be taxable. Your limit for SALT (state and local taxes and sales tax) will be only $5000 per spouse. In many cases you will not be able to take the child and dependent care credit. The amount you can contribute to a retirement account will be affected. If you live in a community property state, you will be required to provide additional information regarding your spouse’s income. ( Community property states:  AZ, CA, ID, LA, NV, NM, TX, WA, WI)

 If  you are using online TurboTax to prepare your returns, you will need to prepare two separate returns and pay twice since with online, you get one return per fee.

https://turbotax.intuit.com/tax-tips/marriage/should-you-and-your-spouse-file-taxes-jointly-or-separately/L7gyjnqyM?srsltid=AfmBOopGqCNexowW0pYgvsf7ycIkrx4VjO_63UXv6vSnfu3UEGQiKQTh

https://ttlc.intuit.com/turbotax-support/en-us/help-article/income/getting-married-mean-taxes/L2RgmagpE_US_en_US?uid=m69on7t0

https://ttlc.intuit.com/turbotax-support/en-us/help-article/taxation/married-filing-separately-community-property/L11CeLUMs_US_en_US?uid=m69ousyh

It depends- there are many variables in the decision to file joint or separate.  See Married Filing Jointly vs Separately: How Should You File?