Suppose the text data in column A is like below,
November 2025 / 80% / MUL
March 2026 / 50% / Situla
February 2026 / 75% / SOP
December 2025 / 75% / MA SIT

Type “80%” or “0.8” in B1 and press Enter can detect pattern and support flash fill now, and the result can auto display with the “%” symbol.