No lease and won't fill out application

[Katelin Eberhard]

Have a tenant who is not on a lease and was not on a lease before COVID19, hasn't paid since January. I have asked her to fill out a lease application and she refuses to, she all of a sudden has all 3 months of rent but still refuses to fill out rental application. I have not taken any payment from her either.. How do I proceed as I do dot want her as a tenant.

Will county illinois