However, I cannot directly provide or attach PDF files. Instead, I can help you find a legitimate, free PDF, or I can of the Sinhala alphabet chart for you to copy into a document and save as PDF.
It sounds like you are looking for a of the Sinhala Akshara Malawa (සිංහල අක්ෂර මාලාව), which is the Sinhala alphabet chart or book.
ක, ඛ, ග, ඝ, ඞ, ච, ඡ, ජ, ඣ, ඤ, ට, ඨ, ඩ, ඪ, ණ, ත, ථ, ද, ධ, න, ප, ඵ, බ, භ, ම, ය, ර, ල, ව, ශ, ෂ, ස, හ, ළ, ෆ Alternative: I can write a short paper ON the Sinhala Akshara Malawa If by "paper" you meant an academic or school paper about the Sinhala alphabet (its history, structure, unique features like the consonant conjuncts, or comparison to other Brahmic scripts), I can write that for you.