I rolled over a 401k from my old company to my new company. I received a 1099-R from my old company. Do I have to enter that amount on my tax return?

[LinaJ2018]

Yes, you have to enter the 1099-R information on your taxes.  As IRS also receives a copy of the 1099-R from your employer, it is important to report the information to match their record.  If it is not taxable, it will show on line 4a as a nontaxable amount for the reporting purposes.