  Optical skyrmion serves as a crucial interface between optics and topology.
Recently, it has attracted great interest in linear optics. Here, we
theoretically introduce a framework for the all-optical generation and control
of freespace optical skyrmions in extreme ultraviolet regions via high harmonic
generation. We show that by employing full Poincare beams, the created extreme
ultraviolet fields manifest as skyrmionic structures in Stokes vector fields,
whose skyrmion number is relevant to harmonic orders. We reveal that the
generation of skyrmionics structure is attributed to spatial-resolved spin
constraint of high harmonic generation. Through qualifying the geometrical
parameters of full Poincar\'e beams, the topological texture of extreme
ultraviolet fields can be completely manipulated, generating the Bloch-type,
Neel-type, anti-type, and higher-order skyrmions, etc. This work promotes the
investigation of topological optics in optical highly nonlinear processes, with
potential applications towards ultrafast spintronics with structured light
fields.
