How to use any Hindi Font in Itext7?

First of all, to retrieve a previously registered font use the PdfFontFactory method CreateRegisteredFont instead of CreateFont. Thus, replace

PdfFont myHindiFont1 = PdfFontFactory.CreateFont("HindiFont1", PdfEncodings.IDENTITY_H, true);

by

PdfFont myHindiFont1 = PdfFontFactory.CreateRegisteredFont("HindiFont1", PdfEncodings.IDENTITY_H, true);

Then, if you want to add text to a paragraph to be drawn in a specific font, first set the font, then add the text. Thus, instead of

iText.Layout.Element.Paragraph Title9 = new iText.Layout.Element.Paragraph("ew[;kad fo'kslrk;sa%");
Title9.SetFont(myHindiFont1);

do

iText.Layout.Element.Paragraph Title9 = new iText.Layout.Element.Paragraph().SetFont(myHindiFont1).Add("ew[;kad fo'kslrk;sa%");

Alternatively you can set that font as document default font:

Document document = new Document(pdf, size);
document.SetFont(myHindiFont1);

iText.Layout.Element.Paragraph Title9 = new iText.Layout.Element.Paragraph("ew[;kad fo'kslrk;sa%");

And finally, add your new paragraph to some entity, e.g.

document.Add(Title9);

The result:

Here the final code I used to successfully render the above screen shot:

String HindiFont1 = @"LEOPALMHINDI15K710.TTF";
PageSize size = PageSize.A4;

PdfFontFactory.Register(HindiFont1, "HindiFont1");

//Error at this line: Font Not Recognized
PdfFont myHindiFont1 = PdfFontFactory.CreateRegisteredFont("HindiFont1", PdfEncodings.IDENTITY_H, true);
//Create Writer
PdfWriter writer = new PdfWriter(@"UseLeopalmhindi15K710LikeDivyanshuAgarwalImproved.pdf");

//Create Pdf Document Object
PdfDocument pdf = new PdfDocument(writer);
Document document = new Document(pdf, size);
//document.SetFont(myHindiFont1);
//String in Title9 Paragraph is a translation of English Phrase
//iText.Layout.Element.Paragraph Title9 = new iText.Layout.Element.Paragraph("ew[;kad fo'kslrk;sa%");
iText.Layout.Element.Paragraph Title9 = new iText.Layout.Element.Paragraph().SetFont(myHindiFont1).Add("ew[;kad fo'kslrk;sa%");

Title9.SetTextAlignment(iText.Layout.Properties.TextAlignment.CENTER);

document.Add(Title9);

document.Close();