When booted into Recovery Mode launch Disk Utility and select the physical drive and erase it as GUID partition and MacOS Extended (Journaled).
If you laptop was running macOS 10.12.4+, then see if you can boot into Internet Recovery Mode with Command + Option + R which would install the latest supported macOS for this laptop. Sometimes even this will still launch the old Mavericks installer. You should still select the physical drive to erase. With newer versions of macOS you may need to click on "View" within Disk Utility and select "Show All Devices" before the physical drive appears in the left pane of Disk Utility.
If a third party SSD is installed in this laptop, then you may require macOS 10.13+ in order to see the physical drive. If this is the case and you cannot access the newer macOS installers in Internet Recovery Mode as I described earlier, then you can download and create a bootable macOS USB installer using another Mac.
https://support.apple.com/en-us/HT201372