react native : How to increase the font?

In my example I want to increase the font of the variablesWhat is the way to increase the font of elem.Sampling_Method_Codein my case ?

var digumMethods = '';    execDetailData.forEach((elem) => {      digumMethods = digumMethods +'\n'+ elem.Sampling_Method_Code +'\n'+ elem.Parameters_String +'\n'+__________'+'\n';    });