A .B64 file is most often a text wrapper for Base64-encoded content, meaning a real file such as a PDF, image, ZIP, or audio has been converted into safe printable characters for transport through systems that might corrupt binary, so when opened in a text editor you’ll see long runs of Base64 symbols—letters, numbers, `+`, `/`, and padding `=`—sometimes wrapped in certificate-style headers or MIME blocks, and decoding restores the original bytes, with common fingerprints like `JVBERi0` for PDFs or `iVBORw0` for PNGs, and remembering that Base64 adds size and offers no encryption or compression.

A .B64 file turns a binary file into portable text enabling smooth travel through email servers, JSON APIs, or web apps that prefer text, and letting developers embed images, certificates, or other small blobs into HTML/CSS or script files, as well as allowing tools to export/import data cleanly, all with the intention that the Base64 be decoded later to recover the true underlying file.

Saying a .B64 file stores encoded bytes instead of raw data highlights that you’re looking at a safe, printable character set instead of the true PDF/ZIP/PNG, because binary isn’t reliable in text systems, and Base64 preserves it until you decode it back into the original usable bytes.

You’ll see .B64 files because Base64 is a dependable way to protect binary in text channels, making email attachments Base64-encoded, APIs returning files in JSON, developers embedding assets in scripts or configs, and migration tools producing copy/paste-safe dumps, all depending on decoding the `.b64` to recreate the original file.

A .B64 file typically contains a Base64 payload made of characters `A–Z`, `a–z`, `0–9`, `+`, `/`, and sometimes `=`, representing the exact bytes of an original file like a PDF, image, ZIP, or DOCX; it may appear as one long line or many wrapped lines, and sometimes includes PEM-style or MIME-style headers, but regardless of formatting, the text must be decoded to recreate the real binary file.

A practical shortcut for figuring out a .B64 file’s decoded output is reading its first Base64 characters: `JVBERi0` almost always means PDF, `iVBORw0` means PNG, `UEsDB` means ZIP/Office formats, and `/9j/` means JPEG; though not foolproof due to potential wrapping or metadata, it’s usually enough to decide whether the decoded file should be saved as `.pdf`, `.png`, `.zip`, `.jpg`, or another type.