See the FAQ: How to do a minimal reproducible example reprex
for beginners.
res_aov <- aov(Sepal.Length ~ Species, data = iris)
shapiro.test(res_aov$residuals)
#>
#> Shapiro-Wilk normality test
#>
#> data: res_aov$residuals
#> W = 0.9879, p-value = 0.2189