It sounds like your daughter would be your dependent as a qualifying child as long as she did not supply more than half her own support.

Qualifying child

RELATIONSHIP: A qualifying child can be your son, daughter, stepchild, eligible foster child, brother, sister, half brother, half sister, stepbrother, stepsister, adopted child or an offspring of any of them.

AGE: The child must be younger than you (or your spouse if filing jointly), AND at the end of the tax year, your child must have been under age 19 (or under 24 if a full-time student). There is no age limit if your child is permanently and totally disabled.

RESIDENCY: Your child must live with you for more than half the year. There are exceptions, such as being away at school, serving in the military, hospitalization and nursing home situations.

SUPPORT: Your child may not have provided more than half of their own support. Scholarships and grants are not considered as support provided by the student.

JOINT RETURN: Your child cannot file on a “Married Filing Jointly” return. (The exception is if they only file to claim a refund)

You cannot file Single, you must file as Married Filing Separately or possible Head of Household if you qualify.

Head of Household is for UNMARRIED taxpayers with a related dependent or married and have not lived with their spouse at anytime during the last 6 months of the tax year AND has a child, stepchild or foster child that can be a dependent.
=======================================
You may be able to file as head of household if you meet all the following requirements.

1. You are unmarried or “considered unmarried” on the last day of the year.
(You could be considered unmarried if your spouse did not live in your home at any time during the last 6 months of the tax year).
If you were considered married for part of the year and lived in a community property state, special rules may apply in determining your income and expenses. See Publication 555 for more information.

2. You paid more than half the cost of keeping up a home for the year.

3. A “qualifying person” lived with you in the home for more than half the year (except for temporary absences such as school) - a parent does not have to live with you to be a qualifying person.

4. If the qualifying person is your qualifying relative, their gross income must have been less than $4,200 (do not include non taxable Social Security) and you provided more than 1/2 of their support

5. You must be able to claim the dependent for the qualifying person except in the case of divorced or separated parents (that lived apart) and the noncustodial parent is claiming the dependent.

A Qualifying person is either:
A qualifying child or a qualifying closely related relative and meets certain other requirements, however if you are considered unmarried it can only be your child, stepchild, or foster child.

See IRS Publication 501 for more information about who is a qualifying person and a worksheet to determine the cost of keeping up a home.

See IRS Pub 501 for more information
https://www.irs.gov/publications/p501#en_US_2018_publink1000220775