Pen or pencil makes no meaningful difference to whether a manifestation succeeds.
The cleanest way to answer this question is to ask what the practice actually changes: attention, behaviour, interpretation, planning, or nothing measurable at all.
Direct answer in practice
The physical writing tool may affect comfort, permanence or aesthetics, but there is no credible reason to treat ink chemistry as a causal manifestation mechanism.
This keeps the practice falsifiable enough to learn from. A rule that explains every outcome after the fact cannot tell you what to change before the next attempt.
What the idea can genuinely do
Use pen if permanence helps commitment; use pencil if revision reduces friction; use digital notes if that is easiest. Before repeating the practice, ask what changed because of it.
Useful outputs include a clearer criterion, a calmer response, a decision, a rehearsal, a plan or a completed action.
What it cannot establish
Material rules can become ritualised until people fear that a smudge, crossing-out or wrong colour has damaged the goal. A warning sign is temporary relief followed by a stronger need to repeat the ritual because uncertainty has returned.
Use this test instead
Choose the tool that makes the exercise easiest to complete and review. Put the result somewhere observable: a calendar entry, checklist, decision rule, progress measure or conversation you can actually complete.
Example from real life
A financial plan written in pencil and updated weekly is more useful than a permanent ink script that cannot adapt to new numbers.
The important part is the causal chain. The practice may influence preparation or behaviour; the external result still depends on the system around it.
Keep the claim proportional
If stationery rules are increasing anxiety, simplify the practice rather than buying more specialised supplies. Money, health, safety, employment and relationships all contain consequences or other people's choices that no inner practice can simply erase.
What to measure
Measure benefit at the level the practice can plausibly affect. The informative variables are what you decide, what you learn and what you do next. A useful page can be messy. Do not demand supernatural proof from a psychological tool or call ordinary progress proof of supernatural causation.
A seven-day experiment
Run a short comparison rather than relying on memory. For one week, use the grounded version of the practice: Use pen if permanence helps commitment; use pencil if revision reduces friction; use digital notes if that is easiest. Keep the goal itself unchanged. Note what you actually do differently and whether the external process receives better inputs from you. If nothing useful changes, you have evidence that the technique may be optional for this goal even if you still enjoy it personally.
A two-minute audit
Use Should you write manifestations in pen or pencil? as a decision question: what is the technique supposed to change, and what evidence would show that change within ordinary life?
Then add: what I can influence next and what evidence will make me review the plan. This keeps the manifestation technique in proportion to the larger strategy.
Bottom line
You can hold spiritual meaning if you choose while still letting external evidence govern high-stakes decisions.
No journal, phrase, tense, mood, visual image or ritual deserves more authority than the evidence and values relevant to the actual goal.
Turn the question into a small experiment
Instead of deciding Should you write manifestations in pen or pencil? from community rules, run a low-cost test. Start with this action: Choose the tool that makes the exercise easiest to complete and review. Keep everything else as stable as practical for a short period. At review, compare your behaviour and evidence with the previous week rather than comparing moods from hour to hour.
The reason for the test is simple: The informative variables are what you decide, what you learn and what you do next. A useful page can be messy. If the practice helps, you will know what it helps with. If it does not, you can simplify without fearing that you have broken an invisible rule.
Quick rule for this question
For Should you write manifestations in pen or pencil?, keep the answer proportional to the real problem: Choose the tool that makes the exercise easiest to complete and review. If that step improves clarity or behaviour, the practice has earned its place. If it mainly increases pressure or checking, simplify it. If stationery rules are increasing anxiety, simplify the practice rather than buying more specialised supplies. That boundary is part of the method, not an obstacle to it.