The phrase "if desired" implies a sense of optionality or preference. There are several synonyms that can be used to convey a similar meaning, such as "if preferred", "if chosen", "if elected", "if opted", "if selected", "if wanted" and "if requested". These terms can be used interchangeably in a sentence, depending on the context and tone of the piece, to give the reader a sense of choice or flexibility. These synonyms can be used in a variety of settings, such as in a menu, survey, or marketing campaign, where the customer's preferences are taken into account.