Texas does not have an income tax so there is no extension to file.
What does Texas have to do with filing an extension? Texas has no state income tax.
EXTENSION
https://turbotax.intuit.com/irs-tax-extensions/
https://ttlc.intuit.com/turbotax-support/en-us/help-article/tax-extension/need-file-extension-personal-state-taxes/L32Mt8ZNv_US_en_US?uid=m9a3q808