Was Windows 10 installed was Bootcamp used to install it? If not, it looks like Windows 10 Wiped the entire drive of anything macOS including the Recovery Partition ( Hidden ).
This link to Apple Support Doc will show how to Create a Bootable Installer of macOS. Make sure one downloads a version of macOS compatible with this computer.
Once the Bootable Installer is completed disconnect all external drives except the newly created Installer. Shutdown computer with the USB Installer attached and startup and Immediately hold the Option key. This should load the Boot Manager and choose to boot to the Bootable Installer.
These next steps with involve Wiping the Entire Drive including the Windows 10 installation so be sure one is prepared for this.
When booted from Installer >> presented with Options and choose Disk Utilities >> View >> View All connected devices. Only left look for the Upper Most Drive usually called Apple SSD or Western Digital or whatever name corresponds to the SSD Makers name. In Toolbar see Partition and choose Partition as One Partition >> Format as HFS Journaled and below that Scheme: GUID Partition Map and then Erase and give the drive name Macintosh HD.
Once done - back out of Disk Utilities and choose Install macOS and follow directions until it reboots to Setup Assist