makeHyperlinkString(sheet, row = 1, col = 1, text = NULL, file = NULL)

## Writing internal hyperlinks
wb <- createWorkbook()
addWorksheet(wb, "Sheet1")
addWorksheet(wb, "Sheet2")
addWorksheet(wb, "Sheet 3")
writeData(wb, sheet = 3, x = iris)

## External Hyperlink
x <- c("https://www.google.com", "https://www.google.com.au")
names(x) <- c("google", "google Aus")
class(x) <- "hyperlink"

writeData(wb, sheet = 1, x = x, startCol = 10)


## Internal Hyperlink - create hyperlink formula manually
writeFormula(wb, "Sheet1",
  x = '=HYPERLINK("#Sheet2!B3", "Text to Display - Link to Sheet2")',
  startCol = 3
)

## Internal - No text to display using makeHyperlinkString() function
writeFormula(wb, "Sheet1",
  startRow = 1,
  x = makeHyperlinkString(sheet = "Sheet 3", row = 1, col = 2)
)

## Internal - Text to display
writeFormula(wb, "Sheet1",
  startRow = 2,
  x = makeHyperlinkString(
    sheet = "Sheet 3", row = 1, col = 2,
    text = "Link to Sheet 3"
  )
)

## Link to file - No text to display
writeFormula(wb, "Sheet1",
  startRow = 4,
  x = makeHyperlinkString(
    sheet = "testing", row = 3, col = 10,
    file = system.file("extdata", "loadExample.xlsx", package = "openxlsx")
  )
)

## Link to file - Text to display
writeFormula(wb, "Sheet1",
  startRow = 3,
  x = makeHyperlinkString(
    sheet = "testing", row = 3, col = 10,
    file = system.file("extdata", "loadExample.xlsx", package = "openxlsx"),
    text = "Link to File."
  )
)

## Link to external file - Text to display
writeFormula(wb, "Sheet1",
  startRow = 10, startCol = 1,
  x = '=HYPERLINK(\\"[C:/Users]\\", \\"Link to an external file\\")'
)
## Not run: 
saveWorkbook(wb, "internalHyperlinks.xlsx", overwrite = TRUE)

## End(Not run)