how change x axis in ggplot2 code example

Example 1: ggplot x axis 45 degreees

q + theme(axis.text.x = element_text(angle = 90, vjust = 0.5, hjust=1))

Example 2: change label x axis ggplot2

theme(
  axis.title = element_text(),         # Change both x and y axis titles
  
  axis.title.x = element_text(),       # Change x axis title only
  axis.title.x.top = element_text(),   # For x axis label on top axis
  
  axis.title.y = element_text(),       # Change y axis title only
  axis.title.y.right = element_text(), # For y axis label on right axis
)