import (
    "os"
    "github.com/aspose-words-cloud/aspose-words-cloud-go/dev/api/models")

config, _ := models.NewConfiguration("config.json")
wordsApi, ctx, _ := api.CreateWordsApi(config)
requestDocument, _ := os.Open("Sample.docx")
requestFontDto := models.Font{
    Bold: ToBoolPointer(true),
}
updateRequestOptions := map[string]interface{}{}
updateRequest := &models.UpdateRunFontOnlineRequest{
    Document: requestDocument,
    ParagraphPath: ToStringPointer("paragraphs/0"),
    FontDto: &requestFontDto,
    Index: ToInt32Pointer(int32(0)),
    Optionals: updateRequestOptions,
}
_, _, _ = wordsApi.UpdateRunFontOnline(ctx, updateRequest)