expand to fit in text and text field

hi

i need to insert a text field in between the text, and this text field should be auto expandable.

ex.

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the employee [field : name of the employee] is working in our org from [start date] to [end date] with salary [salary]. so kindly give him a loan of [amount] with [conditions].........ect..,

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where all content in square bracket differ in size. how this can be achieved.,

reg,

SA