Can I I get free health care

Short answer (assuming you are coming from UK)  - unless you already have Residencia, no.  To get any Spanish healthcare you must firstly be legally resident in the country and as of 1/1/21 pay into private healthcare for one year, after which you can go onto Convenio Especial, which is 60€ per month.

Unfortunately as of 1/1/21 transfer of pension / healthcare rights with an S1 form from DWP was discontinued by UK Government (for anyone first taking residency post 1/1/21)